The invention relates to a method for removing moisture in toluenediamine (TDA), which comprises the following steps: crude TDA obtained through reaction in the previous step is heated in a dehydrating tower, then dehydrated in a dehydrating system and separated in a preseparation tower; ortho-TDA and tar are removed from a separated product containing ortho-TDA, then the product is deeply dehydrated, and meanwhile, the product is subjected to gas stripping with hot nitrogen. On the premise of ensuring the normal operation of a system, the moisture in a TDA product is reduced from 150ppm to below 120ppm, thereby reducing the water volume entering a photochemical reaction system and providing essential safety condition for production safety of the photochemical reaction system.